WO2018008944A1 - Method for managing registration in wireless communication system and device for same - Google Patents

Abstract

A method for managing registration in a wireless communication system and a device for same are disclosed. More particularly, a method, for managing registration in a wireless communication system, performed by a user equipment (UE) which cannot be paged by means of a network and does not perform a periodic registration area update can comprise the steps of: receiving a timer value for managing the deregistered state of a UE from a network during a registration procedure; starting a timer if the UE enters an idle state; and the UE entering the deregistered state if the timer expires.

Description

Registration management method and apparatus for same in wireless communication system

TECHNICAL FIELD The present invention relates to a wireless communication system, and more particularly, to a method for performing / supporting registration management (and / or connection management) and an apparatus for supporting the same.

Mobile communication systems have been developed to provide voice services while ensuring user activity. However, the mobile communication system has expanded not only voice but also data service.As a result of the explosive increase in traffic, a shortage of resources and users are demanding higher speed services, a more advanced mobile communication system is required. have.

The requirements of the next generation of mobile communication systems will be able to accommodate the explosive data traffic, dramatically increase the data rate per user, greatly increase the number of connected devices, very low end-to-end latency, and high energy efficiency. It should be possible. Dual connectivity, Massive Multiple Input Multiple Output (MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Super Various technologies such as wideband support and device networking have been studied.

An object of the present invention is to propose a method of registration management of a UE depending on whether a mobility level of a user equipment (UE) and / or a mobile terminated (MT) service is required.

Another object of the present invention is to propose a detach management method according to whether a mobility level of a user equipment (UE) and / or a mobile terminated (MT) service is required.

In addition, the network is registered in the network through UE (e.g., non-3rd Generation Partnership Project (Non--3GPP) (e.g., Wireless Local Area Network (WLAN)) access that does not require MT services. The UE may not perform a registration area update, a periodic registration area update procedure, or may not be paged. In the case of such a UE, there is a problem that it is not possible to determine whether the UE is detached and when it is detached. Accordingly, an object of the present invention is to propose a registration management method (eg, detach method) for such a UE.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

One aspect of the present invention relates to a registration management method performed by a user equipment (UE) that cannot be paged by a network in a wireless communication system and does not perform periodic registration area update. Receiving a timer value for managing a DEDERIGSTERED state of the UE from the network during a registration procedure; when the UE enters an idle state, starting the timer; If the timer expires, the UE may enter a deregistration state.

According to another aspect of the present invention, a user equipment (UE) for performing a registration management method in a wireless communication system includes a communication module (communication module) for transmitting and receiving signals and a processor for controlling the communication module, The processor receives a timer value for managing a DEDERIGSTERED state of the UE from the network during a registration procedure, starts the timer when the UE enters an idle state. When the timer expires, the UE is configured to enter a DEDERGISTERED state, and the UE cannot be paged by the network and may not perform periodic registration area update. have.

Preferably, when the UE enters the connected state from the idle state, the timer may be reset.

Preferably, when the mobile originated data is generated, if the timer does not expire, a service request procedure may be started.

Preferably, when the mobile originated data is generated, if the timer has expired, the registration procedure can be started.

Preferably, the UE may be a UE set to a limited mobility level at which a service area is limited or to an unlimited mobility level at which a service area is not limited.

Advantageously, regardless of the mobility level of the UE, the UE may not perform a registration area update procedure.

Preferably, when the UE is set to an unlimited mobility level, a service request procedure may be initiated by transmitting an identifier of a serving core network node in a service request message. have.

Advantageously, the UE may be a UE registered with the network through non-3rd Generation Partnership Project (-3GPP) access.

According to an embodiment of the present invention, resource management of the system and the UE is performed by appropriately performing registration management of the UE according to the mobility level of the UE and / or whether the MT service is required. can do.

According to an embodiment of the present invention, UE (eg, non-3GPP (eg, WLAN) access that is not paged and does not perform a (periodic) registration area update, i.e. does not require MT service, is enabled. It is possible to manage the detach (detach) of the UE registered in the network through.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, included as part of the detailed description in order to provide a thorough understanding of the present invention, provide embodiments of the present invention and together with the description, describe the technical features of the present invention.

1 illustrates a 5G system architecture using reference point representations to which the present invention may be applied.

2 illustrates a 5G system architecture to which the present invention may be applied.

3 illustrates an NG-RAN architecture to which the present invention may be applied.

4 is a diagram illustrating a radio protocol stack in a wireless communication system to which the present invention can be applied.

5 is a diagram illustrating a registration management state model in a wireless communication system to which the present invention can be applied.

6 is a diagram illustrating a connection management state model in a wireless communication system to which the present invention can be applied.

7 is a diagram illustrating a 5G core network architecture supporting non-3GPP access to which the present invention may be applied.

8 illustrates an attach procedure (or registration procedure) of a UE for which a limited mobility level is set according to an embodiment of the present invention.

9 illustrates an attach procedure (or registration procedure) of a UE that does not require MT service according to an embodiment of the present invention.

10 is a diagram illustrating a mobility management method according to an embodiment of the present invention.

11 illustrates a CN relocation procedure triggered by a service request according to an embodiment of the present invention.

12 illustrates a block diagram of a communication device according to an embodiment of the present invention.

13 illustrates a block diagram of a communication device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

In this specification, a base station has a meaning as a terminal node of a network that directly communicates with a terminal. The specific operation described as performed by the base station in this document may be performed by an upper node of the base station in some cases. That is, it is obvious that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A 'base station (BS)' may be replaced by terms such as a fixed station, a Node B, an evolved-NodeB (eNB), a base transceiver system (BTS), an access point (AP), and the like. . In addition, a 'terminal' may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), and an AMS ( Advanced Mobile Station (WT), Wireless Terminal (WT), Machine-Type Communication (MTC) Device, Machine-to-Machine (M2M) Device, Device-to-Device (D2D) Device, etc.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal and a receiver may be part of a base station.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of such specific terms may be changed to other forms without departing from the technical spirit of the present invention.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

For the sake of clarity, the following description will focus on the 3GPP 5G (5 Generation) system, but the technical features of the present invention are not limited thereto.

Terms used in this document may be defined as follows.

Evolved Packet System (EPS): A network system consisting of an Evolved Packet Core (EPC), which is a packet switched core network based on Internet Protocol (IP), and an access network such as LTE and UTRAN. UMTS (Universal Mobile Telecommunications System) is an evolved network.

eNodeB: base station of EPS network. It is installed outdoors and its coverage is macro cell size.

International Mobile Subscriber Identity (IMSI): An internationally uniquely assigned user identifier in a mobile communications network.

Public Land Mobile Network (PLMN): A network composed for the purpose of providing mobile communication services to individuals. It may be configured separately for each operator.

5G system (5GS: 5G system): A system consisting of a 5G access network (AN), a 5G core network, and a user equipment (UE)

5G Access Network (5G-AN: 5G Access Network) (or AN): New Generation Radio Access Network (NG-RAN) and / or non-3GPP access network connected to 5G core network 3GPP AN: An access network consisting of a non-5G Access Network.

New Generation Radio Access Network (NG-RAN) (or RAN): A radio access network that has a common feature of being connected to 5GC and supports one or more of the following options:

1) Standalone New Radio.

2) new radio, which is an anchor supporting E-UTRA extensions.

3) standalone E-UTRA (eg eNodeB).

4) anchors to support new radio extensions

5G Core Network (5GC): A core network connected to a 5G access network.

Network Function (NF): A processing function that is adopted by 3GPP or defined in 3GPP in a network. This processing function is defined by a defined functional behavior and an interface defined in 3GPP. Include.

NF service: A function exposed by the NF through a service-based interface and consumed by other authorized NF (s).

Network Slice: Logical network providing specific network capability (s) and network feature (s).

Network Slice instance: A set of NF instance (s) and required resource (s) (e.g. compute, storage and networking resources) forming a network slice to be deployed.

Protocol Data Unit (PDU) Connectivity Service (PDU): A service that provides for the exchange of PDU (s) between a UE and a data network.

PDU Connectivity Service: A service that provides the exchange of PDU (s) between the UE and the data network.

PDU Session: An association between a UE and a data network providing a PDU Connectivity Service. The association type may be Internet Protocol (IP), Ethernet, or unstructured.

Non-Access Stratum (NAS): A functional layer for exchanging signaling and traffic messages between a terminal and a core network in an EPS and 5GS protocol stack. The main function is to support the mobility of the terminal and to support the session management procedure.

5G system architecture to which the present invention can be applied

The 5G system is an advanced technology from the 4th generation LTE mobile communication technology, and is a new radio access technology (RAT) and long-range LTE (Long) through the evolution or clean-state structure of the existing mobile communication network structure. Term Evolution (Extended LTE) technology supports extended LTE (eLTE), non-3GPP (eg, Wireless Local Area Network (WLAN)) access, and the like.

The 5G system is defined as service-based, and the interaction between network functions (NF) in the architecture for the 5G system can be expressed in two ways as follows.

Reference point representation (FIG. 1): NF services in NFs described by a point-to-point reference point (eg N11) between two NFs (eg AMF and SMF) Indicates the interaction between them.

Service-Based Representation (FIG. 2): Network functions (eg AMF) in a Control Plane (CP) allow other authorized network functions to access their services. This expression also includes a point-to-point reference point if necessary.

1 illustrates a 5G system architecture using reference point representations to which the present invention may be applied.

Referring to FIG. 1, the 5G system architecture may include various components (ie, a network function (NF)), which corresponds to some of them in FIG. 1, authentication server function (AUSF). Function), Access and Mobility Management Function (AMF), Session Management Function (SMF), Policy Control Function (PCF), Application Function (AF) ), Unified Data Management (UDM), Data Network (DN), User Plane Function (UPF), (Wireless) Access Network ((R) AN: (Radio) Access Network ) Shows a user equipment (UE).

Each NF supports the following functions.

AUSF stores data for authentication of the UE.

AMF provides a function for UE-level access and mobility management and can be connected to one AMF basically per UE.

Specifically, AMF includes CN inter-node signaling for mobility between 3GPP access networks, termination of Radio Access Network (RAN) CP interface (ie, N2 interface), termination of NAS signaling (N1), NAS signaling security (NAS ciphering and integrity protection), AS security control, registration management (registration area management), connection management, idle mode UE reachability (control of paging retransmission and Mobility management controls (subscription and policy), intra-system mobility and inter-system mobility support, network slicing support, SMF selection, Lawful Intercept (AMF events and LI systems) Interface), providing delivery of session management (SM) messages between the UE and the SMF, transparent proxy for routing SM messages, access Access Authentication, access authorization including roaming authorization checks, delivery of SMS messages between UE and SMSF, Security Anchor Function (SEA), Security Context Management (SCM), etc. Support the function.

Some or all functions of AMF may be supported within a single instance of one AMF.

DN means, for example, an operator service, an Internet connection, or a third party service. The DN transmits a downlink protocol data unit (PDU) to the UPF or receives a PDU transmitted from the UE from the UPF.

-PCF receives the packet flow information from the application server and provides the function to determine the policy of mobility management, session management, etc. Specifically, PCF supports a unified policy framework for controlling network behavior, providing policy rules for CP function (s) (eg, AMF, SMF, etc.) to enforce policy rules, and user data store (UDR). Supports functions such as front end implementation to access related subscription information for policy decision in User Data Repository.

-The SMF provides a session management function, and when the UE has a plurality of sessions, the SMF can be managed by different SMFs for each session.

Specifically, the SMF is responsible for session management (eg, establishing, modifying, and tearing down sessions, including maintaining tunnels between UPF and AN nodes), assigning and managing UE IP addresses (optionally including authentication), and selecting UP functionality. And control, setting traffic steering to route traffic to the appropriate destination in the UPF, terminating the interface towards policy control functions, enforcing the control portion of policy and QoS, and lawful intercept ( For SM events and interfaces to the LI system), termination of the SM portion of NAS messages, downlink data notification, initiator of AN specific SM information (delivered to the AN via N2 via AMF), It supports functions such as determining the SSC mode of the session and roaming functions.

Some or all functions of an SMF may be supported within a single instance of one SMF.

-UDM stores user subscription data, policy data, etc. The UDM includes two parts: an application front end (FE) and a user data repository (UDR).

The FE includes a UDM FE responsible for location management, subscription management, credential processing, and the PCF responsible for policy control. The UDR stores the data required for the functions provided by the UDM-FE and the policy profile required by the PCF. Data stored in the UDR includes user subscription data and policy data, including subscription identifiers, security credentials, access and mobility related subscription data, and session related subscription data. UDM-FE accesses subscription information stored in the UDR and supports features such as Authentication Credential Processing, User Identification Handling, Access Authentication, Registration / Mobility Management, Subscription Management, and SMS Management. do.

The UPF delivers the downlink PDU received from the DN to the UE via the (R) AN and the uplink PDU received from the UE via the (R) AN to the DN.

Specifically, the UPF includes anchor points for intra / inter RAT mobility, external PDU session points of the interconnect to the Data Network, packet routing and forwarding, packet inspection and User plane part of policy rule enforcement, lawful intercept, traffic usage reporting, uplink classifier and multi-homed PDU sessions to support routing of traffic flow to data network. Branching point to support, QoS handling for user plane (eg packet filtering, gating, uplink / downlink rate enforcement), uplink traffic verification (service data flow (SDF) : SDF mapping between service data flow and QoS flow), uplink and downlink transport level packet marking, downlink packet buffering and downlink data notification Functions such as triggering function are supported. Some or all of the functions of the UPF may be supported within a single instance of one UPF.

AF interacts with the 3GPP core network to provide services (e.g. application impact on traffic routing, access to Network Capability Exposure, and interaction with policy frameworks for policy control). It works.

-(R) AN is a new radio that supports both evolved E-UTRA (e-UTRA) and New Radio (NR) (e.g. gNB), an evolution of the 4G radio access technology. Collectively, the access network.

The gNB is capable of dynamic resource allocation to the UE in radio resource management functions (ie, radio bearer control, radio admission control, connection mobility control, uplink / downlink). Dynamic allocation of resources (i.e., scheduling), IP (Internet Protocol) header compression, encryption and integrity protection of user data streams, and routing from the information provided to the UE to the AMF is not determined. The selection of an AMF upon attachment of the UE, routing user plane data to the UPF (s), routing control plane information to the AMF, connection setup and teardown, scheduling and transmission of paging messages (from AMF), system Scheduling and transmission of broadcast information (from AMF or O & M), measurement and measurement reporting settings for mobility and scheduling, and Transport level packet marking on the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in inactive mode, NAS It supports message distribution, NAS node selection, radio access network sharing, dual connectivity, and tight interworking between NR and E-UTRA.

UE means user equipment. The user device may be referred to in terms of terminal, mobile equipment (ME), mobile station (MS), and the like. In addition, the user device may be a portable device such as a laptop, a mobile phone, a personal digital assistant (PDA), a smartphone, a multimedia device, or the like, or may be a non-portable device such as a personal computer (PC) or a vehicle-mounted device.

In FIG. 1, for clarity of explanation, an Unstructured Data Storage Network Function (UDSF), a Structured Data Storage Network Function (SDSF), and a Network Exposure Function (NEF) And NF Repository Function (NRF) are not shown, but all NFs shown in FIG. 1 can interact with UDSF, NEF, and NRF as needed.

NEF is a service provided for 3rd party, internal exposure / re-exposure, application function, edge computing provided by 3GPP network functions. Provide a means for safely exposing the fields and capabilities. The NEF receives information (based on the exposed capability (s) of the other network function (s)) from the other network function (s). The NEF may store the received information as structured data using a standardized interface to the data storage network function. The stored information is re-exposed to other network function (s) and application function (s) by the NEF and may be used for other purposes such as analysis.

NRF supports service discovery. Receives an NF discovery request from an NF instance and provides the NF instance with information about the found NF instance. It also maintains the available NF instances and the services they support.

SDSF is an optional feature to support the storage and retrieval of information as structured data by any NEF.

UDSF is an optional feature to support the storage and retrieval of information as unstructured data by any NF.

Meanwhile, FIG. 1 illustrates a reference model for a case where a UE accesses one DN using one PDU session for convenience of description, but is not limited thereto.

The UE may simultaneously access two (ie, local and central) data networks using multiple PDU sessions. In this case, two SMFs may be selected for different PDU sessions. However, each SMF may have the ability to control both the local UPF and the centralized UPF in the PDU session.

In addition, the UE may simultaneously access two (ie local and central) data networks provided within a single PDU session.

In the 3GPP system, a conceptual link connecting NFs in a 5G system is defined as a reference point. The following illustrates reference points included in the 5G system architecture represented as in FIG.

N1: reference point between UE and AMF

N2: reference point between (R) AN and AMF

N3: reference point between (R) AN and UPF

N4: reference point between SMF and UPF

N5: reference point between PCF and AF

N6: reference point between UPF and data network

N7: reference point between SMF and PCF

N24: reference point between PCF in visited network and PCF in home network

N8: reference point between UDM and AMF

N9: reference point between two core UPFs

N10: reference point between UDM and SMF

N11: reference point between AMF and SMF

N12: reference point between AMF and AUSF

N13: reference point between UDM and Authentication Server function (AUSF)

N14: reference point between two AMFs

N15: reference point between PCF and AMF in non-roaming scenario, reference point between PCF and AMF in visited network in roaming scenario

N16: reference point between two SMFs (in a roaming scenario, a reference point between an SMF in a visited network and an SMF in a home network)

N17: reference point between AMF and EIR

N18: reference point between any NF and UDSF

N19: reference point between NEF and SDSF

2 illustrates a 5G system architecture to which the present invention may be applied.

The service-based interface illustrated in FIG. 2 represents a set of services provided / exposed by a given NF. Service-based interfaces are used within the control plane. The following illustrates a service-based interface included in the 5G system architecture represented as in FIG.

Namf: service-based interface exposed by AMF

Nsmf: service-based interface exposed by SMF

Nnef: service-based interface exposed by NEF

Npcf: service-based interface exposed by PCF

Nudm: service-based interface exposed by UDM

Naf: service-based interface exposed by AF

Nnrf: service-based interface exposed by NRF

Nausf: service-based interface exposed by AUSF

An NF service is a type of ability exposed by a NF (ie, an NF service provider) to another NF (ie, an NF service consumer) via a service-based interface. The NF may expose one or more NF service (s). The following criteria apply to defining an NF service:

NF services are derived from an information flow to describe end-to-end functionality.

The complete end-to-end message flow is described by the sequence of NF service invocations.

The two operations in which the NF (s) provide their services through a service-based interface are as follows:

i) "Request-response": Control plane NF_B (i.e., NF service provider) is responsible for providing a specific NF service (performation of action and / or providing information) from another control plane Request to provide). NF_B responds with NF service results based on the information provided by NF_A in the request.

In order to satisfy the request, the NF_B may in turn consume NF services from other NF (s). In the request-response mechanism, communication is performed one-to-one between two NFs (ie, consumer and supplier).

ii) "Subscribe-Notify"

Control plane NF_A (ie, NF service consumer) subscribes to the NF service provided by another control plane NF_B (ie, NF service provider). Multiple control plane NF (s) may subscribe to the same control plane NF service. NF_B notifies the NF (s) of interest subscribed to this NF service of the results of this NF service. The subscription request from the consumer may include a notification request for notification triggered through periodic updates or certain events (eg, change in requested information, reaching a certain threshold, etc.). This mechanism also includes the case where the NF (s) (eg NF_B) implicitly subscribed to a particular notification without an explicit subscription request (eg, due to a successful registration procedure).

3 illustrates an NG-RAN architecture to which the present invention may be applied.

Referring to FIG. 3, a New Generation Radio Access Network (NG-RAN) provides NR NodeB (gNB) (s) and / or eNB (eNodeB), which provides termination of the user plane and control plane protocol towards the UE. It consists of) (s).

It is interconnected using the Xn interface between gNB (s) and also between gNB (s) and eNB (s) connected to 5GC. The gNB (s) and eNB (s) are also connected to the 5GC using the NG interface, and more specifically to the AMF using the NG-C interface (ie, N2 reference point), which is the control plane interface between the NG-RAN and 5GC. It is connected to the UPF using the NG-U interface (ie, N3 reference point), which is a user plane interface between NG-RAN and 5GC.

4 is a diagram illustrating a radio protocol stack in a wireless communication system to which the present invention can be applied.

4 (a) illustrates the air interface user plane protocol stack between the UE and the gNB, and FIG. 4 (b) illustrates the air interface control plane protocol stack between the UE and the gNB.

The control plane refers to a path through which control messages used by the UE and the network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted.

Referring to FIG. 4A, the user plane protocol stack may be divided into a first layer (Layer 1) (ie, a physical layer (PHY) layer) and a second layer (Layer 2).

Referring to FIG. 4 (b), the control plane protocol stack includes a first layer (ie, PHY layer), a second layer, and a third layer (ie, radio resource control (RRC) layer), It may be divided into a non-access stratum (NAS) layer.

The second layer includes a medium access control (MAC) sublayer, a radio link control (RLC) sublayer, a packet data convergence protocol (PDC) sublayer, a service data adaptation protocol ( SDAP: Service Data Adaptation Protocol (SDAP) sublayer (in case of user plane).

Radio bearers are classified into two groups: a data radio bearer (DRB) for user plane data and a signaling radio bearer (SRB) for control plane data.

Hereinafter, each layer of the control plane and the user plane of the radio protocol will be described.

1) The first layer, the PHY layer, provides an information transfer service to a higher layer by using a physical channel. The physical layer is connected to a MAC sublayer located at a higher level through a transport channel, and data is transmitted between the MAC sublayer and the PHY layer through the transport channel. Transport channels are classified according to how and with what characteristics data is transmitted over the air interface. In addition, data is transmitted between different physical layers through a physical channel between a PHY layer of a transmitter and a PHY layer of a receiver.

2) the MAC sublayer includes a mapping between logical channels and transport channels; Multiplexing / demultiplexing of MAC Service Data Units (SDUs) belonging to one or different logical channels to / from a transport block (TB) delivered to / from the PHY layer via the transport channel; Reporting scheduling information; Error correction through hybrid automatic repeat request (HARQ); Priority handling between UEs using dynamic scheduling; Priority handling between logical channels of one UE using logical channel priority; Padding is performed.

Different kinds of data carry the services provided by the MAC sublayer. Each logical channel type defines what type of information is conveyed.

Logical channels are classified into two groups: Control Channel and Traffic Channel.

i) The control channel is used to convey only control plane information and is as follows.

Broadcast Control Channel (BCCH): A downlink channel for broadcasting system control information.

Paging Control Channel (PCCH): A downlink channel that conveys paging information and system information change notification.

Common Control Channel (CCCH): A channel for transmitting control information between a UE and a network. This channel is used for UEs that do not have an RRC connection with the network.

Dedicated Control Channel (DCCH): A point-to-point bidirectional channel for transmitting dedicated control information between a UE and a network. Used by UE with RRC connection.

ii) The traffic channel is used to use only user plane information:

Dedicated Traffic Channel (DTCH) A point-to-point channel dedicated to a single UE for carrying user information, which may exist in both uplink and downlink. .

In downlink, the connection between a logical channel and a transport channel is as follows.

BCCH may be mapped to BCH. BCCH may be mapped to the DL-SCH. PCCH may be mapped to PCH. CCCH may be mapped to the DL-SCH. DCCH may be mapped to DL-SCH. DTCH may be mapped to the DL-SCH.

In uplink, a connection between a logical channel and a transport channel is as follows. CCCH may be mapped to UL-SCH. DCCH may be mapped to UL-SCH. DTCH may be mapped to UL-SCH.

3) The RLC sublayer supports three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledgment mode (AM).

The RLC configuration may be applied for each logical channel. TM or AM mode is used for SRB, while UM or AM mode is used for DRB.

The RLC sublayer is passed in upper layer PDU; Sequence numbering independent of PDCP; Error correction through automatic repeat request (ARQ); Segmentation and re-segmentation; Reassembly of SDUs; RLC SDU discard; RLC re-establishment is performed.

4) PDCP sublayer for user plane includes sequence numbering; Header compression and decompression (only for Robust Header Compression (RoHC)); User data delivery; Reordering and duplicate detection (if delivery to a layer higher than PDCP is required); PDCP PDU routing (for split bearer); Retransmission of PDCP SDUs; Ciphering and deciphering; Discarding PDCP SDUs; PDCP re-establishment and data recovery for RLC AM; Perform replication of PDCP PDUs.

The PDCP sublayer for the control plane additionally includes sequence numbering; Ciphering, decryption, and integrity protection; Control plane data transfer; Replication detection; Perform replication of PDCP PDUs.

When duplication for a radio bearer is established by the RRC, an additional RLC entity and an additional logical channel are added to the radio bearer to control the replicated PDCP PDU (s). Replication in PDCP involves sending the same PDCP PDU (s) twice. One is delivered to the original RLC entity, the second to an additional RLC entity. At this time, the original PDCP PDU and the corresponding copy are not transmitted in the same transport block. Two different logical channels may belong to the same MAC entity (for CA) or may belong to different MAC entities (for DC). In the former case, logical channel mapping restrictions are used to ensure that the original PDCP PDU and its copy are not transmitted in the same transport block.

5) The SDAP sublayer performs i) mapping between QoS flows and data radio bearers, ii) QoS flow identifier (ID) marking in downlink and uplink packets.

A single protocol entity of SDAP is configured for each individual PDU session. However, two SDAP entities may be configured in the case of dual connectivity (DC).

6) The RRC sublayer is a broadcast of system information related to an access stratum (AS) and a non-access stratum (NAS); Paging initiated by 5GC or NG-RAN; Establishing, maintaining, and releasing RRC connections between the UE and the NG-RAN (in addition, modifying and releasing carrier aggregation), and additionally, dual connectivity between the E-UTRAN and the NR or within the NR. Connectivity); Security functions, including key management; Establishment, establishment, maintenance, and release of SRB (s) and DRB (s); Handover and context transfer; Control of UE cell selection and disaster recovery and cell selection / reselection; Mobility functionality including inter-RAT mobility; QoS management functions, UE measurement reporting and report control; Detection of radio link failures and recovery from radio link failures; NAS message delivery from NAS to UE and NAS message delivery from UE to NAS are performed.

Mobility Management

Registration Management (RM) is used to register or de-register a UE / user to a network and to establish a user context in the network.

1) Registration Management

The UE / user needs to register with the network to receive the service requiring registration. Once registered, the UE, if applicable, periodically maintains reachable (periodic registration update), or on the move (mobility registration update), or updates its capabilities or renegotiates protocol parameters. You can update your registration in the network to do so.

The initial registration procedure includes the execution of a network access control function (ie user authentication and access authentication based on a subscription profile in the UDM). As a result of the registration procedure, the identifier of the serving AMF is registered in the UDM.

5 is a diagram illustrating a registration management state model in a wireless communication system to which the present invention can be applied.

Referring to FIG. 5, two RM states are used in the UE and the AMF to reflect the registration state of the UE in the selected PLMN. FIG. 5 (a) shows the RM state model in the UE, and FIG. 5 (b) shows the RM state model in the AMF.

In the RM DEREGISTERED state, the UE is not registered with the network. The UE context in AMF does not maintain valid location or routing information for the UE and therefore the UE is not reachable by the AMF. However, for example, to prevent the authentication procedure from being performed during every registration procedure, some UE context may still be stored in the UE and AMF.

In the RM DEREGISTERED state, if the UE needs to receive a service requiring registration, the UE attempts to register with the selected PLMN using the initial registration procedure. Or, upon receiving a Registration Reject upon initial registration, the UE remains in the RM DEREGISTERED state. On the other hand, when receiving a Registration Accept, the UE enters the RM-REGISTERED state.

In the RM DEREGISTERED state, when applicable, the AMF approves the initial registration of the UE by sending a Registration Accept to the UE and enters the RM-REGISTERED state. Or, when applicable, rejects the initial registration of the UE by sending a Registration Reject to the UE.

In the RM REGISTERED state, the UE is registered with the network. In the RM-REGISTERED state, the UE may receive a service requiring registration in the network.

In the RM-REGISTERED state, if the Tracking Area Identity (TAI) of the current serving cell is not in the list of TAIs received by the UE from the network, the UE maintains registration and allows the AMF to page the UE. Performs a mobility registration update procedure. Or, to inform the network that the UE is still active, the UE performs a periodic Registration Update procedure triggered by the expiration of the periodic update timer. Or, to update its capability information or renegotiate network and protocol parameters, the UE performs a Registration Update procedure. Or, when the UE no longer needs to register with the PLMN, the UE performs a deregistration procedure and enters the RM-DEREGISTERED state. The UE may decide to deregister from the network at any time. Or, the UE enters the RM-DEREGISTERED state when receiving a Registration Reject message, a Deregistration message, or when performing a local deregistraion procedure without initiating any signaling.

In the RM-REGISTERED state, when the UE no longer needs to be registered with the PLMN, the AMF performs a deregistration procedure and enters the RM-DEREGISTERED state. The AMF may decide to deregister the UE at any time. Or, after the implicit deregistration timer expires, the AMF performs an implicit deregistration at any time. AMF enters the RM-DEREGISTERED state after implicit deregistration. Alternatively, local deregistraion is performed for the UE negotiated to perform deregistration at the end of the communication. AMF enters the RM-DEREGISTERED state after local deregistraion. Or, when applicable, the AMF approves or rejects a Registration Update from the UE. When the AMF rejects a Registration Update from the UE, the AMF may reject the UE registration.

Registration area management includes the ability to assign and reassign a registration area to the UE. The registration area is managed by access type (ie, 3GPP access or non-3GPP access).

When a UE registers with the network via 3GPP access, the AMF allocates a set of tracking area (TA) in the TAI list to the UE. When the AMF allocates a registration area (ie, a set of TAs in the TAI list), the AMF can consider various information (eg, mobility patterns and allowed / non-allowed areas, etc.). An AMF having a whole PLMN (all PLMN) as a serving area may allocate the entire PLMN as a registration area to a UE in MICO mode.

The 5G system supports the assignment of TAI lists containing different 5G-RAT (s) in a single TAI list.

When a UE is registered with the network via non-3GPP access, the registration area for non-3GPP access corresponds to a unique reserved TAI value (ie, dedicated to non-3GPP access). Thus, there is a unique TA for non-3GPP access to 5GC, which is referred to as N3GPP TAI.

When generating a TAI list, the AMF includes only the TAI (s) applicable to the access to which the TAI list is sent.

2) connection management

Connection Management (CM) is used to establish and release a signaling connection between the UE and the AMF. The CM includes the function of establishing and releasing a signaling connection between the UE and the AMF over N1. This signaling connection is used to enable NAS signaling exchange between the UE and the core network. This signaling connection includes both an AN signaling connection for the UE between the UE and the AN and an N2 connection for the UE between the AN and AMF.

6 is a diagram illustrating a connection management state model in a wireless communication system to which the present invention can be applied.

Referring to FIG. 6, two CM states are used, CM-IDLE and CM-CONNECTED, to reflect the NAS signaling connection of the UE with the AMF. 6 (a) shows a CM state transition in a UE, and FIG. 6 (b) shows a CM state transition in an AMF.

The UE in the CM-IDLE state is in the RM-REGISTERED state and does not have an established NAS signaling connection with the AMF over N1. The UE performs cell selection, cell reselection and PLMN selection.

There is no AN signaling connection, N2 connection and N3 connection for the UE in the CM-IDLE state.

In the CM-IDLE state, the UE responds to paging (if received) by performing a service request procedure, unless in MICO mode. Alternatively, when the UE has uplink signaling or user data to transmit, a service request procedure is performed. Or, whenever the AN signaling connection is established between the UE and the AN, the UE enters a CM-CONNECTED state. Or, the transmission of the initial NAS message (Registration Request, Service Request, or Deregistration Request) initiates a transition from the CM-IDLE state to the CM-CONNECTED state. do.

In the CM-IDLE state, if the UE is not in MICO mode, when the AMF has signaling or mobile-terminated data to be sent to the UE, by sending a paging request to the UE, Perform a network triggered service request procedure triggered by. Each time an N2 connection is established between the AN and the AMF for that UE, the AMF enters the CM-CONNECTED state.

The UE in CM-CONNECTED state has a NAS signaling connection with AMF through N1.

In the CM-CONNECTED state, whenever the AN signaling connection is released, the UE enters the CM-IDLE state.

In the CM-CONNECTED state, whenever the N2 signaling connection and the N3 connection for the UE are released, the AMF enters the CM-IDLE state.

When the NAS signaling procedure is completed, the AMF may decide to release the NAS signaling connection of the UE. When the AN signaling disconnection is completed, the CM state in the UE is changed to CM-IDLE. When the N2 context release procedure is completed, the CM state for the UE in AMF is changed to CM-IDLE.

The AMF may keep the UE in CM-CONNECTED state until the UE de-registers from the core network.

The UE in the CM-CONNECTED state may be in an RRC inactive state. When the UE is in the RRC Inactive state, the UE reachability is managed by the RAN using assistance information from the core network. In addition, when the UE is in RRC Inactive state, UE paging is managed by the RAN. In addition, when the UE is in the RRC Inactive state, the UE monitors paging using the CN and RAN identifier of the UE.

The RRC Inactive state is applied to the NG-RAN (ie, to NR and E-UTRA connected to the 5G CN).

Based on the network configuration, the AMF provides assistance information to the NG-RAN in order to assist the NG-RAN in determining whether to switch the UE to the RRC Inactive state.

The RRC Inactive assistance information includes a UE specific DRX value for RAN paging during the RRC Inactive state, and a registration area provided to the UE.

CN assistance information is provided to the serving NG RAN node during N2 activation (ie, during registration, service request, path switch).

The state of the N2 and N3 reference points is not changed by the UE entering the CM-CONNECTED state involving RRC Inactive. The UE in the RRC Inactive state knows the RAN notification area.

When the UE is in a CM-CONNECTED state with RRC Inactive, the UE is in an uplink data pending, a mobile initiated signaling procedure (ie, periodic registration update), a response to RAN paging, or the UE is in a RAN The RRC connection may be resumed due to a notification to the network that the notification area is out of the notification area.

If the UE resumes connectivity at different NG-RAN nodes in the same PLMN, the UE AS context is recovered from the old NG RAN node and the procedure is triggered towards the CN.

When the UE is in CM-CONNECTED state with RRC Inactive, the UE performs cell selection with GERAN / UTRAN / EPS and follows the idle mode procedure.

In addition, the UE in the CM-CONNECTED state with RRC Inactive enters the CM-IDLE mode and follows the relevant NAS procedure in the following cases.

-If the RRC resume procedure fails,

When a UE is required to move to CM-IDLE mode in a failure scenario that cannot be resolved in RRC Inactive mode.

NAS signaling connection management includes the ability to establish and release NAS signaling connections.

The NAS signaling connection establishment function is provided by the UE and the AMF to establish a NAS signaling connection of the UE in CM-IDLE state.

When a UE in CM-IDLE state needs to send a NAS message, the UE initiates a service request or registration procedure to establish a signaling connection to the AMF.

Based on the UE's preferences, UE subscription information, UE mobility pattern and network settings, the AMF can maintain the NAS signaling connection until the UE de-registers from the network.

The procedure of the release of the NAS signaling connection is initiated by the 5G (R) AN node or AMF.

If the UE detects that the AN signaling connection is released, the UE determines that the NAS signaling connection is released. If the AMF detects that the N2 context has been released, the AMF determines that the NAS signaling connection has been released.

3) UE Mobility Restriction

Mobility restriction limits service access or mobility control of the UE in the 5G system. Mobility restriction functionality is provided by the UE, RAN and core network.

Mobility restrictions apply only to 3GPP access, not to non-3GPP access.

In the CM-IDLE state and the CM-CONNECTED state involving RRC Inactive, mobility restriction is performed by the UE based on the information received from the core network. In the CM-CONNECTED state mobility mobility is performed by the RAN and the core network.

In the CM-CONNECTED state, the core network provides the RAN with a Handover Restriction List for mobility restriction.

Mobility restrictions include RAT restrictions, Forbidden areas, and service area restrictions as follows:

RAT Restriction: RAT Restriction is defined as 3GPP RAT (s) in which UE's access is not allowed. The UE in the restricted RAT is not allowed to initiate any communication with the network based on the subscription information.

Prohibited Area: Within the Prohibited Area under the given RAT, the UE is not allowed the UE to initiate any communication with the network based on the subscription information.

Service Area Restriction: Defines the area where the UE may or may not initiate communication with the network as follows:

Allowed area: Within the allowed area under the given RAT, the UE is allowed to initiate communication with the network if allowed by the subscription information.

Non-allowed area: Within the non-allowed area under a given RAT, the UE is limited in service area based on subscription information. The UE and the network are not allowed to initiate session management signaling (both CM-IDLE and CM-CONNECTED states) for acquiring a service request or user service. The RM procedure of the UE is the same as in the allowed area. The UE in the disallowed area responds with a service request to paging of the core network.

For a given UE, the core network determines the service area limitation based on the UE subscription information. Optionally, the allowed zones can be fine-tuned by the PCF (eg, based on UE location, Permanent Equipment Identifier (PEI), network policy, etc.). Service area limitations may change due to, for example, subscription information, location, PEI and / or policy changes. The service area restriction may be updated during the registration procedure.

If the UE has an area overlapping between the RAT restriction, the prohibited area, the allowed area, the not allowed area, or a combination thereof, the UE proceeds according to the following priorities:

The evaluation of the RAT restriction takes precedence over the evaluation of any other mobility restriction;

Evaluation of the prohibited area takes precedence over the evaluation of the allowed and not allowed areas; And

-Evaluation of areas that are not allowed takes precedence over evaluation of areas that are not allowed.

4) Mobile Initiated Connection Only (MICO) mode

The UE may indicate a preference of the MICO mode during initial registration or registration update. The AMF determines whether the MICO mode is allowed to the UE based on the Local setting, preference indicated by the UE, UE subscription information and network policy, or a combination thereof, and informs the UE during the registration procedure.

The UE and the core network re-initiate or exit the MICO mode in the next registration signaling. If the MICO mode is not explicitly indicated within the registration procedure and the registration procedure is successfully completed, the UE and AMF do not use the MICO mode. That is, the UE operates as a general UE, and the network also treats the UE as a general UE.

The AMF allocates a registration area to the UE during the registration procedure. If the AMF instructs the UE in the MICO mode, the registration area is not limited to the paging area size. If the AMF serving area is the entire PLMN, then the AMF may provide the UE with an "All PLMN" registration area. In this case, re-registration with the same PLMN due to mobility does not apply. If mobility restrictions apply to the UE in MICO mode, the AMF assigns the allowed / unallowed areas to the UE.

If the AMF instructs the UE in the MICO mode, the AMF assumes that it is always unreachable while the UE is in CM-IDLE state. AMF rejects any request for downlink data delivery for the UE in MICO mode and CM-IDLE state. AMF also delays downlink transport, such as SMS, location services, etc. over the NAS. The UE in the MICO mode is accessible for mobile terminated data or signaling only when the UE is in CM-CONNECTED mode.

The AMF may provide a Pending Data indication to the RAN node so that the UE in MICO mode can immediately deliver mobile terminated data and / or signaling when switching to CM-CONNECTED mode. When the RAN node receives this indication, the RAN node considers this information when determining user inactivity.

The UE in MICO mode does not need to listen to the paging during the CM-IDLE state. The UE may abort any AS procedure within the CM-IDLE state until the UE in MICO mode initiates the transition from CM-IDLE to CM-CONNECTED mode for one of the following reasons:

When a change in UE (e.g. a setting change) requires a registration update to the network

-Periodic registration timer expires

-MO data is pending

MO signaling is pending

Non-3GPP Access

The 5G core network supports the connection of the UE over a non-3GPP access network (eg WLAN).

7 is a diagram illustrating a 5G core network architecture supporting non-3GPP access to which the present invention may be applied.

N2 and N3 reference points are used to connect standalone non-3GPP access to 5G core network control plane function and user plane function, respectively.

A UE accessing a 5G core network via standalone non-3GPP access supports NAS signaling with the 5G core network control plane function using the N1 reference point after UE attach.

When a UE is connected via NG-RAN and via standalone non-3GPP access, multiple N1 instances for the UE (ie, one N1 instance via NG-RAN and one N1 instance via non-3GPP access) exist.

If the selected Non-3GPP Interworking Function (N3IWF) is located in the same PLMN as the 3GPP access, UEs simultaneously connected to the same 5G core network of the PLMN via 3GPP access and non-3GPP access will be connected to a single AMF. By service.

When a UE is connected to a 3GPP access of a PLMN, if the UE selects N3IWF and the N3IWF is located in a PLMN different from the PLMN of the 3GPP access, the UE is serviced separately by two PLMNs. The UE is registered with two separate AMFs. PDU sessions over 3GPP access are serviced by an SMF that is different from the SMF that serves PDU sessions over non-3GPP access.

PLMN selection for 3GPP is not dependent on N3IWF selection. If the UE is registered via non-3GPP, the UE performs PLMN selection for 3GPP access independently of the PLMN to which the N3IWF belongs.

The non-3GPP access network is connected to the 5G core network via N3IWF. The N3IWF is connected to the 5G core network control plane and the user plane via the N2 interface and the N3 interface, respectively.

The UE establishes an N3IWF IP Security (IPSec) tunnel and attaches to the 5G core network via untrusted non-3GPP access. The UE is authenticated by the 5G core network during the IPSec tunnel establishment procedure and attached to the 5G core network.

After all PDU sessions for the UE over non-3GPP access are released or handed over to 3GPP access, the UE signaling connection with AMF may be maintained.

N1 NAS signaling over standalone non-3GPP access is protected by the same security mechanism applied to N1 over 3GPP access.

For untrusted non-3GPP access, the features of N3IWF are as follows:

i) Support for establishing an IPSec tunnel with the UE: The N3IWF terminates the IKEv2 / IPsec protocol with the UE via NWu, relays the information necessary to authenticate the UE and authenticate access to the 5G core network via N2.

ii) termination of the N2 and N3 interfaces to the 5G core network for the control plane and the user plane, respectively

iii) Uplink and downlink control plane NAS signaling (N1) relay between UE and AMF

iv) N2 signaling control (relayed by AMF) from SMF with respect to PDU session and QoS

v) establishment of an IPsec Security Association (IPsec SA) to support PDU session traffic;

vi) relay of uplink and downlink user plane packets between the UE and the UPF. This includes:

De-capsulation / Encapsulation of Packets for IPSec and N3 Tunneling

QoS implementation corresponding to N3 packet marking, taking into account QoS requirements associated with marking received through N2.

-N3 user plane marking on uplink

local mobility anchor within an untrusted non-3GPP access network

-AMF selection support

Reference points for non-3GPP access are as follows.

Y1: Reference point between UE and non-3GPP access (eg WLAN). This is dependent on non-3GPP access technology.

Y2: reference point between untrusted non-3GPP access and N3IWF for NWu traffic forwarding

NWu: between UE and N3IWF to establish secure tunnel (s) between UE and N3IWF so that control plane and user plane data / signal exchanged between UE and 5G core network can be securely transferred via untrusted non-3GPP access. Reference point.

Registration management method

An Evolved Packet System (EPS) is generally available for UEs with no movement constraints (i.e., all UEs require unrestricted service areas), mobile originated (MO) services, and mobile terminated (MT) services. Designed for the UE.

Accordingly, the UE may perform a normal tracking area update (N-TAU) and periodic TAU (P-TAU) even during an idle (eg, ECM-IDLE or CM-IDLE) period. ) Was required.

N-TAU is a procedure for locating a UE in a tracking area (TA) granularity for registration area management for paging of a UE in a core network (CN) Corresponds to The P-TAU corresponds to a procedure for determining whether the UE is normally registered in the network.

That is, the N-TAU is an operation required for updating the UE to the area where the UE is located when the UE leaves the registration area promised with the MME (ie, a control plane (CP)) during the TAU procedure. The P-TAU is used to manage the registration validity of the UE as a TAU that the UE should perform after a certain time after entering the Idle mode regardless of the location change of the UE.

The network core (MME) immediately starts a detach timer if the P-TAU is not performed at the time when the P-TAU is to be performed, and when the timer expires, the MME determines that the UE has detached and determines the context of the UE. delete context)

In more detail, the P-TAU procedure is used to periodically notify the network of the availability of the UE. This procedure is controlled by the T3412 timer in the UE. The value of the T3412 timer may be sent to the UE by the network in an ATTACH ACCEPT message and may be sent in a TRACKING AREA UPDATE ACCEPT message. The UE applies this value within all tracking areas of the tracking area list assigned to the UE until a new value is received.

When the UE changes from EMM-CONNECTED mode to EMM-IDLE mode, timer T3412 is reset and starts with an initial value. Timer T3412 is stopped when the UE enters EMM-CONNECTED mode or EMM-DEREGISTERED state.

The network supervises the P-TAU procedure of the UE using a mobile reachable timer.

If the UE is not attached for the emergency bearer service, the mobile reachable timer is set longer than T3412.

When the MME releases the NAS signaling connection for the UE, the mobile reachable timer is reset and starts with the set value. When a NAS signaling connection for the UE is established, the mobile reachable timer is stopped.

When the mobile reachable timer expires, the network starts an implicit detach timer. If the implicit detach timer expires before the UE contacts the network, the network implicitly detaches the UE.

That is, if the UE is not contacted by the network by performing a P-TAU until the implicit detach timer expires, the network implicitly detaches the UE.

As described above, the existing wireless communication system (e.g., EPS) is designed such that all UEs are capable of MO service and MT service, so that all UEs are consistently in the IDLE state as described above with N-TAU and P-TAU. It was defined to perform a procedure.

However, since all UEs consistently perform N-TAU and P-TAU procedures, network / wireless resources may be wasted, so that the UE operates in the next generation wireless communication system (for example, 5G system). Instead of doing this, we are studying how to save the resources of the system as well as the UE by limiting the appropriate operation according to the mobility level of various UEs.

That is, resource saving methods are being discussed with regard to mobility levels of different UEs and different traffic patterns (eg, when only MO is required, that is, when MT is not required).

Accordingly, the present invention proposes a registration area management method and a detach management method of the UE according to the mobility level of the UE and the support of a Mobile Terminated (MT) call.

Example 1) Defining a TAU separately into a Registration Area update and a Reachability update

The present invention proposes two levels of UE mobility level consisting of "Limited service area" and "Unlimited service area".

In addition, the present invention proposes a TAU procedure divided into a "Registration Area update" and a "Reachability update" (or periodic registration area update) procedure.

That is, the reachability management for the UE in the IDLE state may refer to a role of detecting whether the UE is accessible and providing a location (ie, an access node) of the UE to the network to reach the UE. This can be done by paging the UE and tracking the UE location. UE location tracking may include UE registration area tracking (ie, registration area update) and UE accessibility tracking (ie, accessibility update or periodic registration area update).

Table 1 illustrates UE idle mode operation with respect to mobility restriction level and MT capability requirement.

Referring to Table 1, a mobility level of a UE may be defined as a greatly limited mobility level (or limited area) and an unlimited mobility level (or unrestricted area). In this case, 'no mobility' may also be classified in the same manner as the limited area.

The mobility (limit) level may be determined based on various conditions such as the subscription data of the UE and the location of the UE, the application the UE is using, the current time and date, and the like.

This mobility (limit) level is stored in the subscription information of the UE and can be adjusted by a policy controller.

When the UE is at an unlimited mobility level, the UE may receive the service without restriction in its PLMN area. This may be referred to as a general type of UE.

On the other hand, in the limited mobility level, a specific UE can be serviced only in a specific area, thereby saving resources of the UE and the network.

A limited mobility level is required in the following example.

Stationary UE

In case of a stationary UE such as a vending machine or a metering machine, mobility support is not required, and thus registration renewal for registration changes is not required.

-Only need service support in certain areas

It mainly corresponds to an enterprise case, and may correspond to a UE used in a museum or an enterprise. That is, a UE used for a specific service in a museum does not need service support when it is outside the museum.

In addition, referring to Table 1, detailed operations of the UE described in Table 1 may be further divided according to whether MT service is required (ie, reachability). That is, a UE requiring MT service may be classified as a reachable UE, while a UE not requiring MT service (ie, MO only) may be classified as an unreachable UE.

As shown in Table 1, the present invention proposes to define whether to perform the registration area update procedure and / or the Reachability update procedure according to the mobility level of the UE and the need for MT service.

In other words, in order to take only the operations required by the existing TAU procedure according to the mobility level of the UE and / or whether the MT service is required, the registration area update procedure and the Reachability Update procedure are separately defined instead of the unified TAU procedure. Suggest.

Registration area update procedure: As an example of this procedure, a TAU triggered when the UE detects entering a new TA that is not in the list of Tracking Area Identity (TAI) (s) it has registered with the network. It may be the same as the procedure.

Reachability update procedure: As an example of this procedure, it may be the same as the periodic TAU procedure triggered when the P-TAU timer expires.

Therefore, when recognizing that the UE moves to a new TA area, a registration area update may be performed, and when reachability update is required after a specific time has elapsed since the UE enters the idle mode, reachability update may be performed.

Referring back to Table 1, in order to maximize resource efficiency in both the UE and the network, a UE that does not require MT service does not perform any TAU procedures (ie, Registration Area update and Reachability Update) and also performs a paging procedure. You can't.

In other words, the UE that does not need the MT service corresponds to the case where only the MO service is supported or the end service (ie, the MT service) is supported only when the UE is in the connected mode. In the case of such a UE, paging generally required for MT service may not be needed.

In addition, in order to manage the paging area, paging monitoring through N-TAU (ie, Registration Area update) and discontinuous reception (DRX) application that is performed when the TA to which the UE belongs is required is required. You can't. Accordingly, as shown in Table 1 above, when the UE does not need MT service, the performance of N-TAU (ie, Registration Area update) and P-TAU (ie, Reachability Update) is limited to limited mobility level and unlimited mobility level. You may not need it all.

On the other hand, a UE that requires MT service and is configured with an Unlimited mobility level requires both N-TAU (ie, Registration Area update) and P-TAU (ie, Reachability Update), and may require a paging procedure.

In addition, for UEs that require MT service and have a limited mobility level, P-TAU (ie, Reachability Update) is required but N-TAU (ie Registration Area update) where TA area is changed is not required. Paging procedures may be necessary.

Embodiment 2) Operation of UE requiring Limited Area / MT Service

According to an embodiment of the present invention, when the mobility level of the UE is a limited area, the UE may not perform a registration area update. This will be described with reference to the drawings below.

8 illustrates an attach procedure (or registration procedure) of a UE for which a limited mobility level is set according to an embodiment of the present invention.

In FIG. 8, AN may correspond to 5G-AN described above, and CP-MM may correspond to AMF.

Referring to FIG. 8, the UE performs an attach procedure (or registration procedure) with the CP-MM (or AMF) via the AN.

If the network (e.g. CP-MM or AMF) recognizes that the mobility level of the UE is limited area by the subscribed information or the like during the attach procedure of the UE, the network attach attach Accept) transmits (or includes) the region information allowed by the service of the UE in the message (S801).

Here, the transmission of the allowed area information may be implemented by including the allowed TA (s) in the attach accept message.

The UE may confirm that the Allow TA (s) is included in an attach accept message or similar message, and may not perform a registration area update procedure thereafter.

However, when MT service is supported (or MT service is allowed from the network), Reachability update and paging reception may be performed to update Reachability.

If the UE does not perform the Reachability update in time, an implicit detach timer may be started to initiate a detach operation. For example, the network (eg, CP-MM or AMF) may run a reachability related timer when the connection is released, such as a NAS signaling connection with the UE. If the UE does not perform the reachability update until the reachability timer expires, the network may start an implicit detach timer. If the UE does not perform the Reachability update until the implicit detach timer expires, the network may implicitly detach the UE.

In this case, the UE may perform the Reachability update procedure by setting the network even when it is out of its allowed TA (s). However, even in this case, if it leaves its allowed TA (s), an operation for receiving a service from the network, such as a service request procedure, may not be performed.

Embodiment 3) Operation of UE that does not require MT service

According to an embodiment of the present invention, a UE that does not need MT service (ie, a UE that only needs MO service) may perform registration area update and reachability update operations regardless of whether the mobility level of the UE is limited or unlimited. You may not do it all.

In addition, in the case of the UE that does not require the MT service, paging reception necessary for the MT service is not necessary, so paging monitoring is unnecessary.

As an example of such a UE, a UE connected to (registered with) a 5G core network through a non-3GPP access network (eg, a WLAN) may correspond thereto.

Hereinafter, for convenience of description, a UE connected (registered) to a 5G core network through a 3GPP access network is referred to as a 3GPP UE, and connected to (registered with) a 5G core network through a non-3GPP access network (eg, a WLAN). The UE is referred to as a non-3GPP UE.

In the existing EPS, the 3GPP core network did not perform mobility management for the Non-3GPP UE, and accordingly, the MME did not perform mobility management for the Non-3GPP UE. Therefore, since the non-3GPP UE is not managed in EPS, handover and the like are not possible.

5G system architecture minimizes the dependency between AN and CN, and is a converged access-agnostic that integrates different cellular (i.e. 3GPP) and non-3GPP access types (e.g. WLAN). (access-agnostic) concept was introduced.

Accordingly, while the AMF controls the non-3GPP UE in the 5G core network, operations similar to those for controlling the 3GPP UE in the previous EPS may be applied (for example, registration and connection state management). have.

That is, in the 5G system corresponding to S1 which is a connection interface between the MME and the eNB in the EPS, both 3GPP UEs (via 3GPP access network) and non-3GPP UEs (via non-3GPP access network and N2IWF) may be connected through N2. (See FIGS. 1 and 7).

In the case of the non-3GPP UE in the existing EPS, since the S1 signaling connection does not exist, when the PDU session is released, it is implicitly regarded as an EMM-DEREGISTERED state. In this case, there is a problem that frequent registration / re-registration occurs due to mobility of the UE.

In the 5G system, since the non-3GPP UE is also connected to the AMF through the same N2 interface as the 3GPP UE, an operation of controlling the non-3GPP UE may be applied similarly to the 3GPP UE.

For example, to prevent frequent registration / re-registration of a non-3GPP UE, even in the case of a non-3GPP UE, the RM-DEREGISTERED state is not immediately switched to the RM-DEREGISTERED state when the signaling connection is released. The CM-IDLE state may be defined in the -REGISTERED state. In other words, to prevent frequent registration / re-registration even when the UE reenters the registration area in a short time after leaving the registration area or Non-3GPP access area. to be.

In this case, the non-3GPP UE in the CM-IDLE state may operate as follows.

For Non-3GPP UEs (ie, UEs registered with the network via non-3GPP access), the registration area for non-3GPP access may be assigned a unique reserved Tracking Area Identity (TAI) (ie non- Dedicated to 3GPP access). Thus, there is a unique tracking area for non-3GPP access to 5GC. This is a value corresponding to the area of the corresponding PLMN. As a result, the non-3GPP UE may not perform a registration area update.

In addition, the UE may not perform periodic registration update (or accessibility update) through non-3GPP access, and a periodic registration timer may not be provided to the UE for non-3GPP access. .

In addition, the UE may not be paged over (untrusted) non-3GPP access.

As a result, the non-3GPP UE in the CM-IDLE state may correspond to an example of a UE that does not require the MT service in Table 1 above.

As described above, the non-3GPP UE may not perform the registration area update and the periodic registration area update (or reachability update) in the CM-IDLE state, and thus, whether or not the UE has been detached from the network, And there is a problem that can not determine when detached.

In order to solve this problem, the present invention proposes an operation of a UE (eg, a UE registered in a network through non-3GPP access) that does not require MT service.

9 illustrates an attach procedure (or registration procedure) of a UE that does not require MT service according to an embodiment of the present invention.

In FIG. 9, AN may correspond to 5G-AN described above, and CP-MM may correspond to AMF.

Referring to FIG. 9, the UE performs an attach procedure (or registration procedure) with the CP-MM (or AMF) via the AN.

When the network (for example, CP-MM, AMF) transmits an attach accept message to a UE of the type, the network transmits the attach valid time together (or includes) (S901). .

Here, the attach valid time corresponds to a timer for managing a DEDERGISTERED state of a UE (eg, a UE registered in a network through non-3GPP access) that does not require MT service. The invention is not so limited, and the attach validity time may be referred to by another name (eg, an implicit deregistration timer).

Attach valid time may be reset when the UE enters a connected mode (ie, CM-CONNECTED state). The attach valid time is run when the UE ends the connected mode (ie, CM-CONNECTED state) (ie, enters idle mode (ie, CM-IDLE state)). .

For example, for (untrusted) non-3GPP access to 5GC, when the Nwu signaling connection between the UE and N3IWF is released, the UE may be interpreted to transition to CM-IDLE state and remain in RM-REGISTERED state. have. Thus, when the Nwu signaling connection is released, the timer can be driven.

Accordingly, when the Attach validity time has not expired at the next MO service (that is, when data to be transmitted to the network occurs), the UE may perform a service request operation. On the other hand, when the attach valid time has already expired in the MO service (that is, when data to be transmitted to the network occurs), the UE performs the attach operation and performs the MO service.

In other words, after the Attach validity time expires, the network may perform implicit detach. Accordingly, after the Attach validity time has expired, the UE may perform a service request procedure again after transmitting an attach request message to the network.

At this time, the network may set a long enough time to the UE as Attach valid time.

As another embodiment, the attach valid time may not be reset when the connected mode is switched, but may be implemented as a time for which the terminal requires reattachment after attaching. That is, when the UE requests the MO service after the attach validity time expires, the terminal may retry the attach procedure and then perform a service request procedure.

As described above, when a UE that does not require MT service has an Unlimited mobility level, the UE may perform a service request procedure before the attach validity time. This will be described with reference to the drawings below.

10 is a diagram illustrating a mobility management method according to an embodiment of the present invention.

Referring to FIG. 10, a UE receives a timer value (ie, attach valid time) for managing a deregistered state from an AMF (or CP-MM) during a registration procedure (S1001).

As described above, here the UE cannot be paged by the network and does not perform periodic registration area update (or accessibility update) (e.g. UE registered with the network via non-3GPP access) May correspond to.

When the UE enters the idle state (ie, the CM-IDLE state), the UE starts a timer (S1002).

Here, for example, for (untrusted) non-3GPP access to 5GC, when the Nwu signaling connection between the UE and N3IWF is released, the UE transitions to CM-IDLE state and remains RM-REGISTERED state. Can be. Thus, when the Nwu signaling connection is released, the timer can be driven.

When the timer expires, the UE enters a deregistered state (S1003).

11 illustrates a CN relocation procedure triggered by a service request according to an embodiment of the present invention.

In FIG. 11, AN may correspond to 5G-AN described above, CP-MM may correspond to AMF, and CP-SM may correspond to SMF.

If the UE that does not require the MT service has an Unlimited mobility level, the UE performs a service request procedure before the attach validity time (S1101). That is, the UE initiates a service request procedure by sending a service request message to the CP-MM (or AMF).

In this case, the UE may include and transmit identification information of a serving CN node of the UE in a service request message.

This is to enable CN relocation when the UE performs a service request procedure before the attach valid time, and leaves the serving CN area due to the movement of the UE.

When the CP node (ie, CP-MM or AMF) that receives the service request message from the UE determines that relocation is necessary (ie, the access node at the current UE location is determined by the previous serving CP node of the UE ( serving CP node, so that a new CN node needs to receive UE context information from an old CP node), a relocation procedure together with a service request procedure. ) May be performed (S1102).

Accordingly, after the relocation of the CN node is completed, a procedure according to the service request may be subsequently performed.

When the service request procedure received from the UE is completed, the CP-MM (or AMF) transmits a service accept message or a user plane setup message to the UE (S1103).

In this case, even in the case of a UE having a limited mobility level, the CN identifier (or identifier) may be used together as an identifier of the UE.

General apparatus to which the present invention can be applied

12 illustrates a block diagram of a communication device according to an embodiment of the present invention.

Referring to FIG. 12, a wireless communication system includes a network node 1210 and a plurality of terminals (UEs) 1220.

The network node 1210 includes a processor 1211, a memory 1212, and a communication module 1213. The processor 1211 implements the functions, processes, and / or methods proposed in FIGS. 1 to 11. Layers of the wired / wireless interface protocol may be implemented by the processor 1211. The memory 1212 is connected to the processor 1211 and stores various information for driving the processor 1211. The communication module 1213 is connected to the processor 1211 and transmits and / or receives a wired / wireless signal. As an example of the network node 1210, the network entity illustrated in FIG. 1 (eg, AMF, SMF, (R) AN, UPF, PCF, etc.) may correspond. In particular, when the network node 1210 is a base station, the communication module 1213 may include a radio frequency unit (RF) for transmitting / receiving a radio signal.

The terminal 1220 includes a processor 1221, a memory 1222, and a communication module (or RF unit) 1223. The processor 1221 implements the functions, processes, and / or methods proposed in FIGS. 1 to 11. Layers of the air interface protocol may be implemented by the processor 1221. The memory 1222 is connected to the processor 1221 and stores various information for driving the processor 1221. The communication module 1223 is connected to the processor 1221 to transmit and / or receive a radio signal.

The memories 1212 and 1222 may be inside or outside the processors 1211 and 1221, and may be connected to the processors 1211 and 1221 by various well-known means. In addition, the network node 1210 (if the base station) and / or the terminal 1220 may have a single antenna (multiple antenna) or multiple antenna (multiple antenna).

13 illustrates a block diagram of a communication device according to an embodiment of the present invention.

In particular, FIG. 13 illustrates the terminal of FIG. 12 in more detail.

Referring to FIG. 13, a terminal may include a processor (or a digital signal processor (DSP) 1310, an RF module (or RF unit) 1335, and a power management module 1305). ), Antenna 1340, battery 1355, display 1315, keypad 1320, memory 1330, SIM card Subscriber Identification Module card) 1325 (this configuration is optional), a speaker 1345, and a microphone 1350. The terminal may also include a single antenna or multiple antennas. Can be.

The processor 1310 implements the functions, processes, and / or methods proposed in FIGS. 1 to 11. The layer of the air interface protocol may be implemented by the processor 1310.

The memory 1330 is connected to the processor 1310 and stores information related to the operation of the processor 1310. The memory 1330 may be inside or outside the processor 1310 and may be connected to the processor 1310 by various well-known means.

The user enters command information such as a telephone number, for example, by pressing (or touching) a button on the keypad 1320 or by voice activation using the microphone 1350. The processor 1310 receives the command information, processes the telephone number, and performs a proper function. Operational data may be extracted from the SIM card 1325 or the memory 1330. In addition, the processor 1310 may display command information or driving information on the display 1315 for the user to recognize and for convenience.

The RF module 1335 is connected to the processor 1310 to transmit and / or receive an RF signal. The processor 1310 communicates command information to the RF module 1335 to transmit, for example, a radio signal constituting voice communication data to initiate communication. The RF module 1335 is composed of a receiver and a transmitter for receiving and transmitting a radio signal. The antenna 1340 functions to transmit and receive radio signals. Upon receiving the wireless signal, the RF module 1335 may deliver the signal and convert the signal to baseband for processing by the processor 1310. The processed signal may be converted into audible or readable information output through the speaker 1345.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in memory and driven by the processor. The memory may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Although the present invention has been described with reference to examples applied to 3GPP LTE / LTE-A system and 5G system, it is possible to apply to various wireless communication systems in addition to 3GPP LTE / LTE-A system and 5G system.

Claims (9)

A registration management method performed by a user equipment (UE) that cannot be paged by a network in a wireless communication system and does not perform periodic registration area update, Receiving a timer value for managing a DEDERIGSTERED state of the UE from the network during a registration procedure; Starting the timer when the UE enters an idle state; And And when the timer expires, entering, by the UE, a DEDERGISTERED state. The method of claim 1, And resetting the timer when the UE enters a connected state from the idle state. The method of claim 1, And initiating a service request procedure when the timer does not expire when mobile originated data is generated. The method of claim 1, And registering the registration procedure when the timer expires when the mobile originated data is generated. The method of claim 1, And the UE is a UE set to a limited mobility level at which a service area is limited or to an unlimited mobility level at which a service area is not limited. The method of claim 5, Regardless of the mobility level of the UE, the UE does not perform a registration area update procedure. The method of claim 1, If the UE is set to an unlimited mobility level, further comprising initiating a service request procedure by transmitting an identifier of a serving core network node in a service request message; Registration management method to do. The method of claim 1, And the UE is a UE registered with the network via non-3rd Generation Partnership Project (-3GPP) access. In a user equipment (UE) for performing a registration management method in a wireless communication system, A communication module for transmitting and receiving a signal; And A processor for controlling the communication module, The processor receives a timer value for managing a DEDERGISTERED state of the UE from the network during the registration procedure, When the UE enters an idle state, the timer is started; When the timer expires, the UE is configured to enter a DEDERGISTERED state, The UE cannot be paged by the network and does not perform periodic registration area update.

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